If you love wine and want to collect and age them, then a wine cellar is a necessity. Wine is alive and it responds to its environment. In fact, a wine's surroundings will determine its ideal maturity date and will also impact its character when it's consumed. There are four key elements that must be controlled for proper long-term wine storage: temperature, humidity, light and vibration.
This is an important long-term storage factor. Temperature levels in a wine cellar must be cool and constant. The generally accepted temperature for storing wine is 55°F, although a range of 50° to 60°F is considered acceptable. White wines prefer it as cool as 45°F. In general, higher temperatures make wines age faster, while cooler temperatures slow the aging process. Higher temperatures may also cause alcohol separation. When temperatures become too low, however, deposits or other suspensions may develop in the wine.
More important than a cool temperature, however, is an even temperature. Sudden or wide fluctuations in a wine's temperature will interrupt the proper aging process. Temperature variations not only shrink and swell the cork, but they may also directly affect the organic components in the wine. Gradual fluctuations of up to 10°F between seasons will not likely damage your wine but more frequent fluctuations of this magnitude will negatively affect the aging process.
For long-term wine storage, a relative humidity of about 65% at approximately 55°F is ideal, however, a range between 60% and 80% is acceptable. Wine is stored on its side so that the wine is in contact with the cork at all times, keeping the cork moist and ensuring a good seal with the bottle.
Lower humidity levels will dry the air-side of the cork, allowing for air leakage or capillary pull action of the wine toward the dry side. This allows oxygen to come in contact with the wine, causing immediate aging.
High humidity levels will not harm the wine. In fact, to a true oenephile, a moldy wine bottle is an indication that the wine has been stored properly for long-term storage. Cardboard boxes will not survive in cellars with high humidity levels, and should therefore be removed from the cellar. These boxes will become soggy and structurally unsound, thus putting your wine at risk when you try to move it.
Ultraviolet light causes premature aging of wines. While wine in clear bottles is most susceptible, wine in dark bottles can be affected as well. Ultraviolet light breaks down some of the complex components and may even produce unpleasant aromas. That's why wine should never be exposed to sunlight for long periods.
Sparkling wines are the most sensitive to light and should be stored in the darkest part of your cellar. Incandescent or sodium vapor lighting are generally better for your cellar than fluorescent light sources, however, as long as light exposure is infrequent, it won't have a negative impact on your collection. Avoid sunlight.
While generally not a problem in residential wine cellars, excessive vibration can disturb a wine's sediment balance. Sediments are meant to fall out of wine and vibration could reintroduce them back into liquid form. Wine should therefore be stored away from vibrations caused by cooling systems or other equipment.
Wine should always be stored away from strong smelling compounds and foods. These odors can penetrate a weak cork and eventually change a wine's character. So don't store your wine in the same closet as fresh garlic!
In general, a temperature of 50° F to 60° F and a Relative Humidity of 60% to 70% are ideal for long-term wine storage. A cool temperature slows the aging process, while high humidity helps to swell the cork, which minimizes oxidation. (Oxidation occurs when air reaches the wine.) Ultraviolet light exposure should be kept to a minimum.
Cool, damp basements or a specially designed wine storage unit are the best ways to achieve these ideal conditions, but even a cool, dark interior closet makes a good place to store wine. If possible, avoid storing wine on a counter in a kitchen, where temperatures can fluctuate dramatically from cooking. And wherever you plan to store your wine, monitor the temperature over a few days first to check it's a good place.